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I don't see any reason not to use this header several times
[quote author=tbct_mt2 link=topic=5095740.msg49551191#msg49551191 date=1549128180]
It doesn't take more space and allows you to be sure all quotes are (or aren't) from the same post/person.
I'd say what you are saying is actually a bad practice that shouldn't be used.
Any quote should have a reference attached to it, be it another post on this very forum, or a link to the website/book/whatever the quote is taken from.